1. Field of the Invention
The present invention relates to a vehicle motion control system for controlling motion of a vehicle in accordance with a tilt of the vehicle when the vehicle is in turning motion.
2. Description of the Related Arts
Recently, a vehicle is provided with an active control suspension system which automatically controls the vehicle's position and comfort. The active control suspension system is adapted to control a hydraulic pressure responsive actuator operatively mounted on each wheel of the vehicle, in response to a driving condition of the vehicle, a road condition and so on, as disclosed for example in a shop manual for a Japanese automobile "Toyota Soarer", issued in May 1991, on pages 3-54 to 3-59.
According to the active control suspension system, the vehicle's position control is performed by determining the vehicle's position on the basis of output signals of various sensors, and controlling pressure control valves so as to keep the vehicle's position substantially stable in any driving conditions. For example, when the vehicle is in turning motion, an anti-roll control is performed by operating an actuator for controlling right and left pressure cylinders, in response to a lateral acceleration of the vehicle which is detected by a lateral acceleration sensor. Consequently, the turning motion of the vehicle is made in such a stable condition that the vehicle's position is kept substantially horizontal.
According to the above-described active control suspension system, however, the actuator and the pressure cylinder controlled thereby are to be provided for each wheel, and the control system will be complicated. Comparing with conventional suspension systems, therefore, number of parts needed for the active control suspension system will be increased, and the system as a whole will become large in scale and high in cost.